Unfortunately, the first part of the expression for the voltage transfer function in Eq. (3) is missing in the original publication. Correctly, the equation should read 1$$ H=\frac{V_1}{V_2}=A-\frac{ (A\cdot Z_T+B )\cdot (A/Z_R+C )}{ (A/Z_R+C )\cdot Z_T+B/Z_R+D}. $$ All figures and results in the original publication have been produced based on the correct equation.

Furthermore, we would like to mention that Eq. (1) should be changed to 2 to be consistent with the current direction defined in Fig. 2(b), although the original equation is correct in itself.

The online version of the original article can be found under doi:10.1007/s00450-012-0228-y.